1. Field of the Invention
The present invention relates to a dust discharging apparatus for use in a dust collector which is designed to collect dust from waste gas discharged from a tall furnace or a sintering apparatus.
2. Related Art
Usually, the dust discharging section of a dust collector is kept at a negative pressure with respect to the surrounding atmosphere. From the aspects of security and public nuisance prevention, the dust discharging section is designed to be hermetically sealed. Specifically, such dust discharging apparatus comprises a series-connection of upstream and downstream dust shoot chambers, the upstream dust shoot chamber being connected to the lower end of a dust hopper. Each dust shoot chamber has a swingable plate-like valve and a valve seat around its ceiling opening.
In operation the swingable plate-like valve of the upstream dust shoot chamber is opened to allow dust to fall from the dust hopper, thus loading the upstream dust shoot chamber with dust. Then, the swingable plate-like valve of the downstream dust shoot chamber is opened to shift the dust from the upstream dust shoot chamber to the downstream dust shoot chamber.
However, when the swingable plate-like valve of the upstream dust shoot chamber is opened to allow dust to fall from the dust hopper, the prevailing negative pressure in the dust hopper causes falling dust to rise and return toward the upstream dust shoot chamber. Then, the valve seat of the swingable valve device of the upstream dust shoot chamber and the associated seal member are exposed to dust blast containing hard particles at high temperature. As a result these members are coated with dust particles, and will be easily worn, and will lose sealing effect after a relatively short time. This requires frequent change of expensive seal members.